My advice would be don't be in a rush to live anywhere travel Thailand and see what fits for you. I've lived a few places in Thailand now and prefer the islands in the south currently 2 years in koh tao. Rent fully furnished place a month at time and when you find what makes you happiest then make the decision.
i actually went into immigration with my thai family and the staff there had no idea about the family extension ( it is a small office though and not the main immigration for the province)
Have you been to immigration and asked if you can use 60day thai family extension? You are allowed once per visit i believe but not sure if can have following a covid extension
When I have applied for thai pass I uploaded the policy front page, with your name and policy number etc and also uploaded the page that specifically said covid cover ( mine was in section F )
I haven't actually been asked to show any income and my application is now complete, I was given this by the local amphur in Bangkok but didn't end up using that amohur in the end so maybe some requirements are amphur specific.